Radiation of elastic waves from sources embedded in anisotropic inclusions

Abstract

SUMMARY We develop an explicit formulation of the far-field Green's tensor in an anisotropic inclusion surrounded by an otherwise isotropic and homogeneous elastic medium. The technique handles all anisotropic systems without exception (21 independent elastic constants), but is restricted to cases where the size of the inclusion is small with respect to both the source-receiver distance and the wavelength. Hence, the application of the approximation is restricted to sources in localized regions of anisotropy so that errors related to geometrical spreading and propagation direction will be negligible. The predictions of our model are of interest for application to signals generated by sources in seismic exploration as well as nuclear test monitoring.